Process of flame retarding substrates by applying hexahydratriazine phosphonate derivatives

ABSTRACT

Method of flame retarding substrates by applying Hexahydrotriazine phosphonate derivatives corresponding to the structural formula:   WHERE R5 and R6 are the same or different radicals and are   AND R1, R2, R3 and R4 are the same or different radicals and are alkyl, cycloalkyl, alkenyl, alkylene, aryl or aralkyl said radicals having 1 to 20 carbon atoms and are either unsubstituted or substituted by non-interfering substituents such as halogen, alkoxy, or hydroxy; and mixtures thereof and curing at a moderate temperature by free radical initiation or radiation so as to form an insoluble, fire retardant resinous finish.

1 1 Sept. 16, 1975 1 1 PROCESS OF FLAME RETARDING SUBSTRATES BY APPLYINGHEXAHYDRATRIAZINE PHOSPHONATE DERIVATIVES [75] Inventor: Edward D. Weil,

Hastings-on1-luds0n, N.Y.

[73] Assignee: Stauffer Chemical Company,

Westport, Conn.

221 Filed: Aug.30, 1974 211 App]. No.: 501,928

Related US. Application Data [601 Division of Ser. No, 178,417, Sept. 7,1971, Pat. No.

3,849,409, which is a continuationin-part of Scr. No. 139,222, April 30,1971, Pat. No. 3,762,865.

[52] US. Cl. 428/262; 8/116 P; 8/190; 252/81; 427/40; 427/54; 427/372;427/390; 428/265; 428/267; 428/268; 428/921;

Primary Examiner-J0hn H. Newsome [5 7 ABSTRACT Method of flame retardingsubstrates by applying Hcxahydrotriazine phosphonate derivativescorresponding to the structural formula:

where R and R are the same or different radicals and are 7. t -crt cn;and CXl, -Cl 1 0R4 and R, R R and R are the same or different radicalsand are alkyl, cycloalkyl, alkenyl, alkylcne, aryl or aralkyl saidradicals having 1 to 20 carbon atoms and are either unsubstituted orsubstituted by noninterfering substituents such as halogen, alkoxy, orhydroxy; and mixtures thereof and curing at a moderate temperature byfree radical initiation or radiation so as to form an insoluble, fireretardant resinous finish.

13 Claims, No Drawings PROCESS OF FLAME RETARDING SUBSTRATES BY APPLYINGI-IEXAHYDRATRIAZINE PI-IOSPI-IONATE DERIVATIVES CROSS-REFERENCE TORELATED APPLICATION This application is a division of application Ser.No. 178,417 filed Sept. 7, 1971, now U.S. Pat. No. 3,849,409 which was acontinuation-in-part of application Ser. No; 139,222 filed Apr. 30,1971, now U.S. Pat. No. 3,762,865.

BACKGROUND OF THE INVENTION In the above noted co-pending application,there is disclosed a process for flame retarding solid flammablesubstrates, such as textiles, comprising the application l to 3 moles ofdiallyl phosphite to the double bonds of triac ryloylhexahydrotriazine.

SUMMARY OF THE INVENTION Thus, it is one object of this invention toprovide novel hexahydrotriazine phosphonate derivaives whigh are usefulas flame retarding agents.

Another object of the present invention is to provide a flame retardanttextile or other solid substrate finishing process which is operable atambient or moderately elevated temperatures and which can employ eitheran aqueous or organic solvent application medium.

A further object of the instant invention is to provide a flameretardant finishing process which is suitable for use with textiles madefrom either natural or synthetic fibers as well as with blends of eachof the latterfiber types.

A still further object of this invention is to provide a flame retardantfinishing process for various other flammable, solid substrates such,for example as synthetic resins, paper, wood, batting and rope, whichare capable of being impregnated, admixed with and/or coated with aflame retardant, resinous finish.

DESCRIPTION OF THE PREFERRED EMBODIMENTS N Cg CH N-CO- R5 cu R CO Nwherein R and R are the same or different radicals and are selected fromthr group consisting of and wherein R, R, R and R are the same ordifferent and are radicals selected from the group consisting of alkyl,cycloalkyl, alkenyl, alkylene, aryl, and arylalkyl; said R, R R and Rradicals having from 1 to about 20 carbon atoms and either substitutedor unsubstituted by non-interfering substituents selected from the groupconsisting of halogen, alkoxy and hydroxy, wherein the terminal valencyof any such alkylene radical is linked to the same phosphonatefunctional group, such as via a cyclic-methylene chain or linked toanother phosphonate functional group conforming to structural formula Isuch as via a straight chain of methylene groups or via a series ofcyclic-methylene chains connected through a spiro carbon; and mixturesof these phosphonate derivatives. Illustrative of alkyl are,

for example, methyl, ethyl, propyl, isopropyl, butyl,

amyl, hexyl, octyl, eicosyl and the like; illustrative of cycloalkylare, for example, cyclopropyl, cyclopentyl, cyclohexyl, cyclooctyl andthe like; illustrative of alkenyl,which is defined herein as anunsaturated monovalent radical, are, for example, allyl, crotyl,linoleyl and the like; illustrative of alkylene, which is defined hereinas a saturated divalent radical, are, for example, ethyl-.ene,,tetramethylene neopentylene, 1,2-propylene, hexretardantefficiency, it is preferred that R, R R or R be CfC, lower alkyl, C Calkenyl or C C, alkylene such as methyl, ethyl, propyl, isopropyl,butyl, isobutyl, ally], ethylene, propylene, etc., or C -C brominated orchlorinated lower alkyl, alkylene or alkenyl having only beta and/orgamma halogens, rather than higher carbon containing radicals. However,for certain specific reasons, such as for greater water repellency it issometime advantageous to utilize OA -C 0 alkyl or alkenyl, alkylene orhalogenated alkyl, including polyfluoroalkyl.

Examples of specific compounds represented by the above structuralformula (I) are:

f cu

cr., r

L ca co u /N co-cu c11 (vx n) Cll- Cli-CO-N N-CO-CH-Cl'h;

These new hexahydrotriazine phosphonate derivatives of the instantinvention are readily prepared by means of the base-catalyzed additionof about I to 3 moles of the appropriate phosphite or phosphitesrepresented by the formula:

bis(2-ethoxyethyl), bis(2,3-dichloropropyl), bis(2,3- dibromopropyl),diphenyl, dicresyl, bis( nonylphenyl), bis( 2,4,6-trichlorophenyl bis(2,4-dibrom0phenyl methyl phenyl, dibenzyl, di-p-bromobenzyl,dicyclohexyl,

-Continued 7 u n and mc moc s o P o c n, c n, 9 II I! v n which arereadily separated from the mixtures by conventional procedures such asfractional crystallization or chromatography.

In conducting this reaction, the particular disubstituted phosphite andl,3,S-triacryloylhexahydro- 1,3,5-triazine may be combined in theabsence ofa solvent or they may be mixed in a suitable inert solvent.Generally, however, when a l to l or 2 to 1 adduct is being prepared, itis preferred to employ an inert solvent which is capable of dissolvingall or a substantial portion of the triacryloylhexahydrotriazine.Solvents particularly suitable for this purpose include dioxane,dimethoxyethane, tetrahydrofuran and methylene chloride. Methylenechloride, however, is most preferred.

Of course, these solvents are also suitable for use in preparing any ofthe 3 to l adducts contemplated within the scope of this invention.Other solvents also suitable for this purpose include benzene, tolueneand acetone. The selected base catalyst which can be sodium methylate,potassium or sodium metal which appears to form the phosphite anion insitu), lithium alkyl, methylmagnesium bromide, sodium amide,tetramethylguanidine, triethylenediamine, an alkali metal hydroxide orany other suitable basic material capable of abstracting a proton fromthe HPO(OR) compound, is then introduced into the reaction mixture in aconcentration of from at about 0.001 to 10 percent,

as based upon the disubstituted phosphite, at about 0 to 150 C.resulting in an exothermic reaction which may cause the mixture to boil,or which may be moderated by external cooling. The reaction is observedto be complete when the phosphate is substantially all consumed, asmeasured by infrared or other assay.

In another embodiment, the present invention relates to the processcomprising the application to a textile, or other flammable solidsubstrate, followed by curing, of an effective flame retarding amount ofat least one hexahydrotriazine phosphonate derivative correspond-1 ingto structural formula 1. These flame retardant compounds are applied toa fabric or other substrate at a concentration of from about 5 to about50 percent, as calculated on the dry weight of the substrate, and arethereafter cured, i.e., polymerized, so as to form an insoluble, fireretardant, resinous finish by free radical initiation using either achemical initiator or actinic radiation in order to induce the desiredreaction.

While the use of aqueous solutions comprises the most economical meansof application for these hexahydrotriazine phosphonate derivatives, theymay also, if desired, be applied to a normally flammable substrate ocgn,oc mcnh o to 20.

while dissolved in any of the organic solvents commonly used in thesolvent finishing of textiles including for example, trichloroethylene,dichloroethane, trichloroethane, perchloroethylene, methylene chloride,etc., and mixtures thereof including emulsified mixtures with water. Thesolutions, either aqueous or organic solvent, containing one or more ofthe selected hexahydrotriazines phosphonate derivatives may be appliedto textiles or other substrates by the use of any desired procedure. Itis merely necessary to have the particular phosphonate or phosphonatesevenly absorbed throughout the mass of the textile, or other substrate,and/or to apply it to at least one surface thereof by means of anyconvenient procedure. Accordingly, it may be applied by being sprayedonto one or both surfaces of the substrate or, as is more frequently thecase, the substrate may be passed or padded through the solution whilethe latter is being held in a tank or other suitable container. Such aprocess is commonly referred to as a padding technique" with thesolution being referred to as a padding bath or padding solution.

The concentration of the hexahydrotriazine phosphonate derivative withinthe padding bath, or other applicable solution, will be dependent upon anumber of factors including, in the case of textile substrates, thenature of the fibers which comprise the textile substrates, the natureof the fibers which comprise the textile, the weight and weave of thetextile, the degree of flame retardancy that is desired in the finishedtextile, as well as other technical and economic considerations knownand understood by those skilled in the art. However, it is generallydesirable that the padding bath should contain an amount of thephosphonate such that when the wet uptake is reduced to a dry depositupon the textile or other substrate, the treated substrate will containfrom about 5 to percent of the hexahydrotriazine phosphonate derivativeas based upon the dry weight of the substrate. Again, it is to bestressed that the latter limits are merely illustrative and may bevaried so as to provide a finished article having any desired degree offlame retardancy.

The thus applied hexahydrotriazine phosphonate derivative may be curedin the wet state or it may be completely or', most preferably, partiallydried before curing. Of course, it is realized that thehexahydrotriazine phosphonate derivatives encompassed by the presentinvention which do not contain double bonds, i.e., ethylenicunsaturation, are to be utilized as additive flame retardants since theyare not curable. Typical applica tions for these compounds include theiraddition to viscous rayon, before spinning or to plastics before moldingin order to enhance their flame retardancy.

On the other hand, the mode of curing in accordance with the process ofthis invention involves the use of a free radical reaction in order toinduce the double bond, i.e.,. the ethylenic unsaturation, of both thealkenyl, such as allyl, and/or acryloyl groups present in thesecompounds to polymerize intermolecularly so as to form a cross-linked,insoluble resin in and/or on the individual fibers, or other structuralelements, which comprise the textile or other substrate. Thus, thehexahydrotriazine phosphonate derivatives of the present invention whichpossess both the alkenyl, such as ally], and acryloyl groups areespecially preferred because they allow for wide variations in the speedand temperature of cure and yield highly desirable products as a resultof the presence of these varied unsaturated groups. It is understood, ofcourse, that the present invention includes the use of mixtures of thesehexahydrotriazine phosphonate derivatives described above as reactiveflame retardants wherein only one or more of said hexahydrotriazinephosphonate derivatives in the mixture contains ethylenic unsaturation.

Free radical initiation of the desired polymerization reaction may beinduced either by the use of those chemical catalysts known as freeradical initiators or by the use of the actinic radiation. Suitable freeradical catalysts encompass peroxygen compounds, which may be used aspart of a so-called redox system which contains a chemical reducingagent in addition to the peroxygen compound, and azo compounds. Examplesof suitable peroxygen catalysts are hydrogenperoxide, which is oftenused in conjunction with ferrous salts; ammonium, sodium or potassiumpersulfate; t-butyl hydroperoxide, benzoyl peroxide, lauroyl peroxide;dicumyl peroxide; cumene hydroperoxide; t-butyl peroxypivalate; methylethyl ketone peroxide; caprylyl peroxide and tert-butylperoxymaleicacid, and acetyl peroxide. Examples of suitable azo catalysts includeazobisisobutyronitrile and azobisisovaleronitrile. These catalystsshould be used in an effective amount in the range of from about 0.1 topercent, by weight, of the allyl phosphonate flame retardant; theprecise amount required being dependent upon the tightness of the cure,i.ei, the degree of crosslinking, which is required as well as theextent to which free radical chain inhibiting substances such as oxygenhave been excluded from the system.

Actinic radiation, encompasses high energy protons and other particlescapable of initiating free radical reactions including ultravioletlight, x-rays, gamma rays, alpha rays, beta rays, i.e., electron beamradiation and plasma, i.e., highly ionized atoms in the vapor state suchas present in an electrical corona or glow discharge. A preferred sourceof actinic radiation involves the use of an electron beam, i.e., betaradiation, since equipment adaptable for textile and paper anill use isv readily available and is eminently suited for rapid, continuousprocessing. In any event, regardless of the type of actinic radiationthat is used, it should be applied in an effective dosage in the rangeof from about 0.1 1O megarads; the exact dosage being dependent on thetightness of cure required, the amount of inhibitors present and thegeometry and nature of the substrate.

Where a cure is induced by the use of a free radical catalyst, theselected catalyst is generally activated by heating up to about 200 C.but, preferably, in the range of from about to 165 C. so as to minimizeany thermal damage to the substrate. Alternatively, the catalyst can beactivated, even at ambient temperatures, by applying a reducing agent tothe textile or other substrate either before or after applying the flameretardant reagent and catalyst. Suitable reducing agents include sulfurdioxide, ferrous salts, such as the halides and sulfates, as well assulfurous, phosphorous, or hypophosphorous acids and their water solublesalts such, for example, as sodium bisulfite, sodium phosphite andsodium hypophosphite. The catalyst may also be activated by actinicradiation.

When actinic radiation is used, either alone or in combination with afree radical catalyst, it is only nec essary to expose the substrate toa beam from a radiation source. If desired, this can be done at ambienttemperature thus sparing the substrate from thermal damage.'The exposurecan be conveniently conducted by passing the substrate through the beamwhich may be produced, for example, by a bank of ultraviolet lamps,corona-discharge points, a cobalt-6O source, an x-ray source or anelectron beam source. Reasonably homogenous radiation flux is desirablewhere an electron beam is used, thus the beam can be transverselyscanned at a rapid rate across the substrate so as to evenly irradiateall points thereon. If desired, a suitable mechanical arrangement ofrollers can be employed so that the substrate can be made to repeatedlypass through the radiation field thereby facilitating more complete useof the available radiation flux while also obtaining more uniformirradiation.

The use of radiation initiation does not generally require the use of achemical activator. However, the efficiency of the radiation canfrequently be improved by use of such an activator. Suitable activatorsfor this purpose include ketones, such as acetone or benzoin; polycyclichydrocarbons, such as polyphenyl; and, azo compounds such asazobisisobutyronitrile. Where an electron beam is used, the applicationof about 0. 1-10 megarads, at a voltage sufficient tosubstantiallypenetrate the substrate to the depth to which the .flame retardantpolymer is to be formed, generally suffices to effect the desired cure.

The resulting cure, or polymerization, of the hexahydrotriazinephosphonate derivative which is induced by either a catalyst and/oractinic radiation generally takes place on the surface and within thebody of the fibers, or other structural elements, which comprise thesubstrate. Moreover, in some cases the resulting polymer network may begrafted, or chemically bonded, on to the fiber molecules of the textileor other substrate. However, such grafting is not crucial to theattainment of a durable, flame retardant finish.

The irradiation of the substrate is usually carried out subsequent tothe application of the phosphonate although, in the case of cellulosicfibers which can be irradiated so as to form stable, long lived freeradical sites, the phosphonate compound can be applied subsequent toirradiation whereupon it will proceed to cure.

The process of this invention may, if desired, include the use of otherfree radical curable, i.e., polymerizable, comonomers, along with theselected hexahydrotriazine phosphonate derivative as a means ofachieving variations in the properties of the resulting treatedtextiles. Thus, suitable optional comonomers for use in conjunction withthese phosphonates include:

1. Monomers containing an amide nitrogen such as acrylamide,methacrylamide, N-methylolacrylamide, diacetonylacrylamide,hydroxymethylated diacetonylacrylamide, methylenebisacrylamide, N-vinylpyrrolidone and cellulose grafted N- methylolacrylamide, the use ofthe latter monomer being disclosed in U.S. Pat. No. 3,434,161. The useof these amide nitrogen containing comonomers at a concentration ofabout 0.1-6 moles per mole of the phosphonate, permits a more economicalfinish, particularly with cellulosic fibers, since less of the morecostly phosphonate monomer needs to be used in order to achieve a givenlevel of flame retardancy.

2. Monomers containing more than one polymeriz able double bond such,for example, as the polyol polyacrylates or methacrylates, the glycoldiacrylates, the glycol dimethacrylates, methylenebisacrylamide,triallylphosphatc, alkyl divinylphosphinates, diallyl allylphosphonateand triallyl cyanurate. By using this class of comonomers, the crosslinkdensity of the resulting finish can be increased thereby enhancing itsdurability with respect to wear and laundering.

3.- Monomers contributing to flame retardancy, i.e., monomers havingphosphorus, bromine or chlorine atoms in their molecules including, forexample, vinyl and vinylidene halides such as vinyl chloride, vinylbromide, vinylidene chloride, vinylidine bromide and vinylidenechlorobromide; chloroprene; triallyl phosphateydiallyl allylphosphonate;diallyl cyanoethylphosphonate; diallyl carboxyethyl phosphonate; dialkylvinylphosphonates such as dicthyl vinylphosphonate,bis(2-chloroethyl)vinylphosphonate or its polycondensation products;and, in general all of the unsaturated phosphonate monomers disclosed inmy copending applications Ser. Nos. 23,493 now abandoned and 23,499, nowPat. No. 3,695,925 both filed Mar. 27, 1970 and including all the allyl2-carbamoylalkylphosphonates disclosed in the hereinabove identified andrelated copending application. When utilized in the process -of thisinvention, these optional comonomers can'be present inthe system in awide range of concentrations depending on the function of the comonomerand desired properties of the final product.

lt should be noted, at this point, that the use of the term crosslinkedin describing the cured, fire retardant resins resulting from thepolymerization of the selected hexahydrotriazine phosphonate derivativein the finishing process of this invention will indicate to thoseskilled in the art that these resins possess a highly intermeshed,three-dimensional configuration or network rather than a simple linearor branched structure of the type found in non-erosslinked copolymers.Thus, such crosslinked polymers may be further characterized by the factthat they will not lose more than about percent of their total weightupon being extracted with methanol in a Soxlet extractor. Moreover, asused in this disclosure, the term fire retardant is intended to refer tothat particular property of a material which provides it with a degreeof resistance of ignition and burning. Thus a fire or flame retardanttextile, paper or other solid substrate is one'which has a low level offlammability and flame spread. This property may be convenientlyevaluated by means of any of the standard flame retardancy tests.

The process of this invention is compatible with a wide variety of othertextile finishing operations which can be carried out prior,simultaneous with, or subsequent to the process of the invention. Theseother operations include application of durable press, softening,antistatic, abrasion resistance, water-repellent, soilrelease, andantimicrobial finishes, as well as bleaching, dyeing, printing, flockingand texturing.

Thus, the finishing formulations of the invention may also optionallycontain other types of ingredients known in the textile finishing art.For example, water and soil repellents, optical brighteners andcolorants, softening agents such as polyethylene emulsions,handmodifying agents, buffering agents, pHcontrolling agents which maybe acidic or basic, emulsified waxes, chlorinated paraffins, polyvinylchloride, polyvinylidene chloride, homoand copolymers of the alkylacrylates and other resinous finishing agents may be added inconjunction with the finishing agents of the invention. And, where anextremely high degree of flame retardance is required, it is alsopossible to employ systems containing antimony oxide, a resinous binder,particuarly one containing chlorine such as a chlorinated paraffin orpolyvinyl chloride, along with the phosphonates required in the processof this invention. Moreover, in treating wood and paper substrates, thefire retardant finishes of this invention may be applied along with andas part of an aminoplastic binder resin. And, when used for finishingpaper, these hexahydrotriazine phosphonate derivatives can be used inconjunction with any of the various adhesives, coatings sizes, wetstrength additives and other materials which are ordinarily employed inthe paper finishing art.

All types of textiles may be treated by means of the process of thisinvention so as to provide them with durable, fire retardant finishes.Thus, one may treat textiles derived from natural fibers such as cotton,wool, silk, sisal, jute, hemp and linen, wood and from synthetic fibersincluding nylon and other polyamides; polyolefins such as polypropylene,polyesters such as polyethylene terephthalate; cellulosics such asrayon, cellulose acetate and triacetate; fiber glass (which is flammablewhen coated with organic sizing agents); acrylics and modacrylics, i.e.,fibers based onacrylonitrile copolymers; saran fibers, i.e., fibersbasedon vinylidene chloride copolymers; rubber based fibers; spandex fibers,i.e., fibers based on a segmented polyurethane; vinal fibers, i.e.,fibers based on vinyl alcohol copolymers; vinyan fibers, i.e,, fibersbased on vinyl chloride copolymers; and, metallic fibers. Textilesderived from blends of any of the above listed natural and/or syntheticfibers may also be treated by means of the process of this invention.

Where the fibers are of the synthetic types made by melt spinning orsolvent spinning, the compounds of the invention may be added to themelt or solution before spinning and cured thereafter, such as byirradiation.

As used in this disclosure, the term textiles" is meant to encompasswoven or knitted fabrics which consist of continuous or discontinuousfibers bonded so as to form a fabric by mechanical entanglement, thermalinterfiber bonding or by use of adhesive or bonding substances. Suchnon-woven fabrics may contain a certain percentage, up to percent ofwood pulp as well as conventional textile fibers in which case part ofthe bonding process is achieved by means of hydrogen bonding between thecellulosic pulp fibers. ln nonwoven fabrics, the finishing agents ofthis invention can serve not only as flame retardant finishes, but canalso contribute to the interfiber bonding mechanism by serving as all orpart of the adhesive or bonding resin component. This dual role can alsobe played by the finishing agents of this invention in fabric laminateswhere the finishing agent can at the same time serve as the interlaminarbonding agent and as the flame retardant. In both of these systems,i.e., non-woven fabrics and laminated fabrics, the finishing agents ofthis invention can also be blended with the usual bonding agents such,for example, as acrylic emulsion polymers, vinyl acetate homoandcopolymer emulsions, styrene butadiene rubber emulsions, urethane resinemulsions, polyvinyl chloride emulsions, vinyl chloride-alkyl acrylatecopolymer emulsions, polyacrylates modified by vinyl earboxylic acidcomonomers and the like.

It should also be noted, at this -point, that in addition to being usedto provide flame retardant finishes for textiles, the above describedhexahydrotriazine phosphonates can also be employed for the flameretarding of a wide variety of polymeric substrates such as cellulose inthe form of paper, wood, plywood, chipboard,

jute, batting and the like; urethane foams, coatings and elastomers;aminoplast resins and phenolic resins as well as their composites withpaper, wood flour and the like; alkyd coatings and molding resins; and,paints and varnishes derived from natural or synthetic resins. Forexample, the hcxahydrotriazine phosphonate derivatives of this inventionare admixed with unsaturated polyester resins. In particular, thephosphonates of this invention possessing unsaturation may be cured withthe unsaturated polyester to provide durably flame retardant curedproducts from which the flame retardant cannot last by volatility or bysolvent leaching. More over, the compounds of this invention, in.particular those having multiple unsaturation may be'admixed with vinylpolymers, rubber or polyolefins and cured, for instance by radiation orperoxides to increase the heat and flame resistance of the polymer, thusimproving its utility for applications such as wire and cableinsulation.

Having generally described the invention, the following examples aregiven for purposes of illustration. It will be understood that theinvention is not limited to these examples, but is susceptible todifferent modifications that will be recognized by one of ordinary skillin the art.

EXAMPLE 1 This example illustrates the preparation of thehexahydrotriazine phosphonate derivative corresponding to structuralformula I where R and R are CH%H and R and R are methyl.

To 95.6 g. of 1,3,S-triacryloylhexahydro-1,3,5- triazine in 200 cc. ofmethylene chloride is added 42.7 g. of dimethyl phosphite and g. oftetramethylguanidine (as a basic catalyst). The solution is refluxedovernight and then evaporated at 100 C. at aspirator vacuum to obtain awater soluble pale yellowish syrup. NMR analysis of the product mixtureshowed that one CH =CHCO group and two (CH O) P(O)CH CH- CO groups arepresent per three NCH groups.

EXAMPLE 2 This example illustrates the preparation of thehexahydrotriazine phosphonate derivative corresponding to structuralformula] where R is -CH CH PO( OCH R is CH=CH and R and R are methyl.

Using the method of Example 1, 95.6 g. of 1,3,5-triacryloylhexahydro-l,3,5-triazine and 85 g. of dimethyl phosphite isreacted to obtain the indicated product as a water soluble syrupexhibiting 3 vinylic protons and 12 methoxy protons per 6 NCH --Nprotons in the NMR analysis.

EXAMPLE 3 This example illustrates the preparation of thehexahydrotriazine phosphonate derivative corresponding to structuralformula 1 where R and R are both CH CH PO(OCH;,) and R and R are methyl.

A mixture of 62.8 g. of l,3,S-triacryloylhexahydro- 1,3,5-triazine, g.of dimethyl phosphonate, and 3 g. of tetramethyl guanidine is mixed,heated to C. and then worked up as in Example 1. The crude product, acolorless solid, is recrystallized from benzene to obtain the purecrystalline compound having a m.p. of 1024 C. The infrared spectrumindicates the absence of C=C bonds, supporting the structure:

Anal. Calculated for C ,H;,,;O, N;,P;,: P 16.05, N 7.25;

Found: P 15.8, N 7.0.

EXAMPLE 4 This example illustrates the preparation of the diallylphosphite adducts of l,3,S-triacryloylhexahydro-1,3,5- triazine.

'lo 43.8 parts by weight of diallyl phosphite and 22 parts of1,3,5-triacryloylhexahydro-1,3,5triazine in 120 parts of methylenechloride, 1 part of sodium methoxide is added with stirring. Anexothermic reaction occurs causing the mixture to boil, under reflux,for about 15 minutes. After 30 minutes, infrared examination of a sampleof the reaction mixture shows no pH structures present. The reactionmixture is then stripped free of solvent under reduced pressure, leavingthe desired product, i.e., the 3:1 adduct of diallyl phosphite and1,3,S-triacryloylhexahydro-l,3,5-triazine as an amber syrup [1 1.5091.lnfrared analysis of the structure indicates the absence of the P-H bondat 2420 cm, the absence of the CH:=CHCO double bond at 1612 cm, and thepresence of a phosphonate P=O at 1240-1250 cm. The yield issubstantially quantitative. I

In a like manner, the 1:1 and 2:1 adducts of diallyl phosphite and l,3,S-triacryloylhexahydro- 1 ,3,5- triazine are prepared by employing14.6 parts and 29.2 parts, respectively, of diallyl phosphite in theabove procedure.

EXAMPLE 5 This example illustrates the preparation of a thermoset resinof a hexahydrotriazine phosphonate derivative corresponding tostructural formula I.

A mixture of the product of Example 1 and l percent, by weight, ofbenzoyl peroxide is heated to 100 C. for 1 hour in a mold. A clear,light yellow, hard molded object is obtained which is rapidlyselfextinguishing when ignited by a burner flame.

EXAMPLE 6 This example illustrates the preparation of a textile flameretarding finish by means of the process of this invention.

An aqueous solution of 26.5 g. of the product of Example l and 0.5 g. ofammonium persulfate is prepared and padded onto pieces of cotton andDacron, i.e., polyethylene terephthalate, cloth. The cloths are wrungout to a wet add-on of 70-80 percent, then cured by ex- EXAMPLE 8 Thisexample illustrates the use of the product of Example 3 as an additiveflame retardant according to the POSliI'C to steam for A: hour andfinally oven-dried at 5 process of this invention. 100 areself'extmgulshmg both before and Self-extinguishing films of celluloseacetate are preafter laundermg' pared containing percent of the productof Example EXAMPLE 7 3 which is incorporated by admixture with asolution of the cellulose acetate in alcohol-acetone prior to the Thisexample again illustrates the preparation of a 10 casting of the textileflame retarding finish by means of the process of this invention.

A 35 percent aqueous solution of the product derived EXAMPLE 9 y l'moles of dimethyl l l to 1 mole of This example illustrates a comparisonof the flame 13a5'tl'lacryloylhexahydm'13,tnaZme as Prepared 15retarding characteristics of the hexahydrotriazine phosy the method ofExample 1 1S Padded Onto a P phonate derivatives of this invention witha related (ethylenfa tefepllthalate) Polypropylane a ccftton prior artflame retardant on a cellulosic substrate. cloth, dried in air and thethus treated cloths irradiated Solutions are made up of 1) the adduct of3 moles by 5 megarads of 300 kv. beta radiation using a Dynaof dianylphosphite and 1 mole of 1,3,5 coat electron accelerator (manufactured byRadiation triacryloylhexahydrwl,3,5 triaZine prepared accord Dynamics,westbufy, New York) e resuling to Example 4, and 2 the adduct of 1 moleof dialtant cloths are washed with hotwater and then giyen an lylphosphite and 1 mole of acrylonitrile each of 1) accelerated launderingby boiling for 3 hours with 0.2 and (2) being formulated at 2 gllo and 4gm Cc Pement s* Percent 9 1 Solutlon- Testmg of using water as thesolvent for (l) and methanol as the the fabrlcs indicates the followmgresults? solvent for (2). Paper sheets are impregnated with TABLE 1these four solutions, dried in air, and cured by one days exposure, atroom temperature, to the radiation Fabric %P analysis by X-rayfluorescence Flammability from a high pressure mercury arc pv w theresults bdmc aft r after ft of the evaluation of the dry add-on andflammability 2 Wash "2 Wash SOdu boil Soda boil before and after washingin running water for 15 min- Sen: utes are tabulated below in Table 2.The flammability Cotton 1.68 1.78 1.08 extinguishing is determined bythe match angle test of the U5.- l f r zl lcne i212 i 22 D.A.-S.R.R.L.,Beninate et a1, Textile Research Journal, 369370, (1969).

TABLE 2 Before Washing After Washing g/cc. Dry Add-on Flammability* DryAdd-on Flammability 0 01 OR COC'H CH P 1 \OR- CH CH 2 37.4 -1-1+ 33.3-H+ RCOl J /lLCO-R" 4 67.7 +1-1- 63.5 -H+ Where R" and R are both 0R3!CH2CH2P and R.

R, R", and R1 are ally].

( O "I (CH CHCH O CH C C a N 2 7.4 i 1.0

Symbols; -burns in any position. isome samples self-extinguishing inhorizontal position, dsclf-extinguishing in horizontal position.Hself-cxtinguishing at H-l-self-exlinguishing in vertical position.

EXAMPLE This example illustrates the use of a hexahydrotriazinephosphonate derivative of this invention in flame retarding anunsaturated polyester.

TABLE 3 MATERIAL LO] Unsaturated polyestcr l7.7 Unsaturated polyesterand 10% 20.75

3:l diallyl phoshitc/triacryloylhexahydrotriazine adduct.

In the ner like to Examples 14, the following addition reactions areperformed, in each case using 1,3,-S-triacryloylhexahydro-l,3,5-triazine as one of the reactants:

Added Nature of Example Molcs/ Adduct No. Phosphitc Used Mole Solvent,T'C. Catalyst TAHHT [(CH;,),CHO]. ,PHO 1,5 CH OCH CH OCH Sodium Syrup, 11 -70% Metal, water 0.1% soluble (C H OhPHO l CH CI tctrawaxy methylsolid 12 guanidinc tri Crystalline l3 3 None (melt) ethylene Solid l()0diaminc CH; CH O sodium Wax 14 C PHO l None (melt) methylate Solid CH CH-O 100 l dioxane do. Viscous l5 Hoc H oc u oPoc H oc H OH -100 Syrup ldioxane do. Viscous H syrup l6 i.

HOC H OC H O IFOC H OC H, OH

l tetra- Viscous (CH BrCHBrCH O) PHO CH Cl methyl syrup 17 refluxguanidine 1% sodium Wax OCH CH O 1/2 CH CI methylate, l8 OHP I c PHOReflux 0.5%

OCH CH O (C H -,O) PHO CH Cl do. Viscous syrup l9 and l+l Reflux (CH O)PHO water soluble I 3 20 CH OPHQOCH CH=CH do. do. Syrup To anunsaturated polyester (of the type made by esterifying phthalic andmaleic anhydrides with a glycol and then diluting the polyester withstyrene) is added 10 percent by weight of the 3 to 1 adduct of diallylphosphite and l ,3,S-triacryloylhexahydrol ,3 ,5- triazine madeaccording to Example 4. The resin mixture is then cured by heating at100 C. for 10 hours with 1 percent benzoyl peroxide. The flammability ofthe resultant cured polyesters is evaluated by the limiting oxygen index(LOl) method as described by Fenimore and Martin, Modern Plastics, 44,14.1 1966). The resultant value, which represents the minimum oxygenconcentration (in mole percent) at which a rod of the polymer willcontinue to burn when ignited at the top in a vertical position, areillustrated as follows in Table 3 below. Thus, a higher L0] isindicative of a higher degree of flame retardancy.

In addition to their use as flame retarding agents, the allylphosphonate hexahydrotriazine derivatives of this invention are usefulas chemical intermediates for the production of the correspondingglycidyl esters with for example, peracetic acid, said esters beinguseful as reactive flame retardants and finishing agents for textiles.

Obviously, numerous modifications and variations of the presentinvention are possible in the light of the above teachings. It istherefore to be understood that within the scope of the appended claimsthe invention may be practiced otherwise than as specifically describedherein.

What is claimed is:

1. A process for flame retarding flammable solid substrates comprisingapplying to the substrate an effective amount of at least onehexahydrotriazine phosphonate derivative corresponding to the structuralformula:

wherein R and R are the same or different radicals and are selected fromthe group consisting of CH=CH and and wherein R, R R and R" are the sameor different and are radicals selected from the group consisting ofalkyl, cycloalkyl, alkenyl, alkylene, aryl, and arylalkyl; said R, R, Rand R" radicals having from 1 to about carbon atoms and eitherunsubstituted or substituted by non-interfering substituents selectedfrom the group consisting of halogen, alkoxy and hydroxy, wherein theterminal valency of any such alkylene radical is linked to the same oranother phosphonate molecule conforming to the above formula with theproviso that when R and R are both at least one of R, R R and R" isalkenyl; and thereafter curing said phosphonate so as to form aninsoluble. fire retardant resin in and/or on said substrate.

2. The process of claim 1 wherein said al kenyl is ally] and saidphosphonate is applied to said substrate in a concentration of fromabout 5 percent to about 50 percent calculated on the dry weight of saidsubstrate.

3. The process of claim 1 wherein the curing of said phosphonate iseffected in the presence of an effective amount of a free radicalinitiating catalyst.

4. The process of claim 1 wherein the curing of said phosphonate iseffected by exposure to an effective amount of actinic radiation.

5. The process of claim 4 wherein the curing of said phosphonate iseffected by exposure to an effective amount of electron beam radiation.

6. The process of claim 1 wherein the curing of said phosphonate iseffected by exposure to an effective amount of actinic radiation whilein the presence of a free radical initiating catalyst.

7. The process of claim 1 wherein at least one optional comonomer isapplied to the substrate in conjunction with said phosphonate.

8. The process of claim 1 wherein said phosphonate is applied to saidsubstrate in the form of an aqueous solution.

9. The process of claim 1 wherein said phosphonate is applied to saidsubstrate in the form of an organic solvent solution.

]0. The process of claim 1 wherein said substrate is a textile.

11. A process for flame retarding flammable solid substrates comprisingthe addition to said substrate of an effective amount of at least onehexahydrotriazinc phosphonate derivative corresponding to the structuralformula:

O I II 0R CUCIL en; p I OR N CK ca l l wherein R and R are and whereinR, R, R and R are the same or different radicals and are selected fromthe group consisting of CH=CH and 0 a II and wherein R, R", R and R" arethe same or different and are radicals selected from the groupconsisting of alkyl, cyeloalkyl, alkenyl, alkylene, aryl, and arylalkyl;said R, R R and R" radicals having from 1 to about 20 carbon atoms andeither unsubstituted or substituted by non-interfering substituentsselected from the group consisting of halogen, alkoxy and hydroxy,wherein the terminal valency of any such alkylene radical is linked tothe same or another phosphonate molecule conforming to the aboveformula.

12. A flame retardant substrate produced by the process of claim 1.

13. A flame retardant substrate produced by the process of claim 11.

UNITED STATES PATENT AND TRADEMARK OFFICE CERTIFICATE OF CORRECTIONPATENT N0. 1 3,906,156 DATED September 16, 1975 |N\/ ENTOR(S) Edward D.Weil It is certified that error appears in the above-identified patentand that said Letters Patent are hereby corrected as shown below: Cole.2 and 5, Formulae II, III and VII: The portion on the extreme left handside should read CH =CH-C0-I I Col. 5, Formula VII: The portion in theextreme upper right hand side should read:

--P O-CH -CH=CH Col. 5, Formulae VIII, IX, X and XI: the two portionsattached to the nitrogen heteroatoms in the lower part of the formulaeshould read:

-- CH =CHC0- and -CO-CH=CH respectively;

Col. l r, line 5: change "62.8" to 62.5

Col. 15, Table 2, Formula I: Change 'R" at the extreme left hand side ofthe structural formula to R UNITED STATES PATENT AND TRADEMARK OFFICECERTIFICATE OF CORRECTION PATENT NO. 1 5,906,156 DATED September 16,1975 my gmomg Edward D. Weil It is certified that error appears in theabove-identified patent and that said Letters Patent are herebycorrected as shown below:

Claim 11, the first and second formulae should correspond to theformulae at Col. 1, lines 57 and following and at Col. 2, lines Signedand Sealed this sixteenth Day Of December 1975 [SEAL] Arrest:

RUTH C. MASON C. MARSHALL DANN Arresting Officer Commissioner ufParentsand Trademarks

1. A PROCESS FOR FLAME RETARDING FLAMMABLE SOLID SUBSTRATES COMPRISINGAPPLYING TO THE SUBSTRATE AN EFFECTIVE AMOUNT OF AT LEAST ONEHEXAHYDROTRIAZINE PHOSPHONATE DERIVATIVE CORRESPONDING TO THE STRUCTURALFORMULA:
 2. The process of claim 1 wherein said alkenyl is allyl andsaid phosphonate is applied to said substrate in a concentration of fromabout 5 percent to about 50 percent calculated on the dry weight of saidsubstrate.
 3. The process of claim 1 wherein the curing of saidphosphonate is effected in the presence of an effective amount of a freeradical initiating catalyst.
 4. The process of claim 1 wherein thecuring of said phosphonate is effected by exposure to an effectiveamount of actinic radiation.
 5. The process of claim 4 wherein thecuring of said phosphonate is effected by exposure to an effectiveamount of electron beam radiation.
 6. The process of claim 1 wherein thecuring of said phosphonate is effected by exposure to an effectiveamount of actinic radiation while in the presence of a free radicalinitiating catalyst.
 7. The process of claim 1 wherein at least oneoptional comonomer is applied to the substrate in conjunction with saidphosphonate.
 8. The process of claim 1 wherein said phosphonate isapplied to said substrate in the form of an aqueous solution.
 9. Theprocess of claim 1 wherein said phosphonate is applied to said substratein the form of an organic solvent solution.
 10. The process of claim 1wherein said substrate is a textile.
 11. A process for flame retardingflammable solid substrates comprising the addition to said substrate ofan effective amount of at least one hexahydrotriazine phosphonatederivative corresponding to the structural formula:
 12. A flameretardant substrate produced by the process of claim
 13. A flameretardant substrate produced by the process of claim 11.